The typhoon that hit Mindanao in the Philippines before Christmas to claim 1,000 lives and leave nearly 50,000 homeless was a shock, but not a surprise. In 2009, campaigners and scientists simulated the effects of a tropical storm on the island, and predicted that the cities of Cagayan de Oro and Iligan would be hit by flash floods. At the time, the prediction was dismissed as alarmist. The scientists were conducting an exercise as part of a UN strategy for disaster reduction, to which 168 nations signed up in 2005. They did their bit: they identified a natural hazard. But the Philippine government had yet to enact its own disaster management plan; the two coastal cities remained without protection, and catastrophic flooding affected more than 300,000 people. The lesson is pertinent, but not new. Three years before Hurricane Katrina devastated New Orleans in 2005, there were warnings about the city's vulnerability. Katrina still somehow surprised a complacent government. Forewarned turns out not to be forearmed. Knowledge is power only for those prepared to act upon it.

Such lessons are worth learning. With 80 million new souls on the planet each year, most of them in the developing world, the numbers of potential victims will go on increasing. And as the planet warms, so too does the potential for meteorological disaster. Not all disasters relate to the climate, but rising levels of greenhouse gases could double the probability of catastrophic rainfall and other weather extremes. In 2011 the United States has already experienced one of the worst years on record, with a 1,000 dead in a dozen disasters, each exacting a financial toll of $1bn or more. The total cost of these 12 assaults by tornado, wildfire, drought, blizzard, flood and heatwave is put at $52bn. The number of events that meet the UN definition of a natural disaster has risen steadily with each decade, and catastrophic floods, windstorms and so on have become everyday events: in 2010, there were 385, and they killed 297,000 worldwide. The tally for 2011 is not complete, but the auguries are ominous.

Natural disasters can devastate communities, distort economies and set back development, and they tend to do their worst, for predictable reasons, to the poorest communities. Many such hazards can be identified and much of the damage they do could be pre-empted. The problem, confronted every day by the scientists, medics and economists who have to pick up the pieces, is persuading governments and communities to begin systematic preparation for the next time around. Authorities know what to do in the face of climate change, the question is whether they will do it.

This year also showed, however, that even if people know enough to foresee and prepare for climate-related hazards, they can still be taken unawares by geophysical forces. Japan is the most earthquake-conscious society on the planet, its engineers are the most sophisticated. Tsunami – all too often generated by seismic shock – is a Japanese word. And yet the magnitude 9 Tohoku earthquake that hit Japan in March took both a nation and its scientists by surprise: the violence was 100 times greater than anything anyone had expected. The tsunami that followed within minutes was a surge of unbelievable force. Satellite images later showed that two wave fronts had merged to form one single ocean wave of colossal destructive power: a freak event that had been hypothesised, but never observed. A closer look at the geological evidence of the last 2,000 years has since shown that such megaquakes and megastunamis have hit the region before.

In 2011, too, volcanologists again raised the spectre of a massive eruption of Vesuvius, and the decades-old question of how to evacuate the 3 million citizens of Naples in an emergency. We still need to know much more about the planet, but even when we do know, it seems, we fail to act.